Fix reindex concurrency

lib/philomena_query/search.ex

@@ -201,13 +201,17 @@ defmodule PhilomenaQuery.Search do
   """
   @spec reindex(queryable(), schema_module(), Batch.batch_options()) :: :ok
   def reindex(queryable, module, opts \\ []) do
+    max_concurrency = Keyword.get(opts, :max_concurrency, 1)
     index = @policy.index_for(module)
 
     queryable
-    |> Batch.record_batches(opts)
-    |> Enum.each(fn records ->
+    |> Batch.query_batches(opts)
+    |> Task.async_stream(
+      fn query ->
         lines =
-        Enum.flat_map(records, fn record ->
+          query
+          |> Repo.all()
+          |> Enum.flat_map(fn record ->
             doc = index.as_json(record)
 
             [
@@ -217,7 +221,11 @@ defmodule PhilomenaQuery.Search do
           end)
 
         Api.bulk(@policy.opensearch_url(), lines)
-    end)
+      end,
+      timeout: :infinity,
+      max_concurrency: max_concurrency
+    )
+    |> Stream.run()
   end
 
   @doc ~S"""